Non-invasive prospective targeting of arterial PCO2 in subjects at rest
Non-invasive prospective targeting of arterial PCO2 in subjects at rest
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DOI：
10.1113/jphysiol.2008.154716
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发表时间：
2008-08-01
影响因子：
5.5
通讯作者：
Fisher, Joseph A.
中科院分区：
文献类型：
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作者：
Ito, Shoji;Mardimae, Alexandra;Fisher, Joseph A.
动脉P-CO2（P-a，P-CO2）的精确测量目前需要血液采样，因为呼出气体的潮气末P-CO2（P-ET，P-CO2）通常不能准确反映平均肺泡P-CO2和P-a，P-CO2。P-ET、P-CO2和P-a、P-CO2之间的差异是由于灌注和气体交换的区域不均匀性造成的。我们假设，通过顺序气体输送回路进行呼吸将充分减少这些不均匀性，以允许根据P-ET、P-CO2准确预测P-a、P-CO2。我们在5名健康中年男性中通过比较他们的P-ET、P-CO2值与P-a、P-CO2值在P-ET、P-CO2（35至50 mmHg）、P-O2（70至300 mmHg）和呼吸频率（f; 6至24次呼吸min（-1））的各种组合下的P-ET、P-CO2值来验证这一假设。一旦每个个体处于稳定状态，通过连续血样一式两份采集P-a、P-CO2，以评估其重复性。P-ET、P-CO2和平均P-a、P-CO2之间的差异为0.5 +/- 1.7 mmHg（P = 0.53; 95% CI-2.8，3.8 mmHg），而两次P-a、P-CO2测量值之间的平均差异为-0.1 +/- 1.6 mmHg（95% CI-3.7，2.6 mmHg）。重复测量方差分析显示，在P-O2，f和目标P-ET，P-CO2范围内，P-ET，P-CO2和P-a，P-CO2之间无显著差异。我们得出结论，当通过顺序气体输送回路呼吸时，P-ET，P-CO2提供了与动脉血的实际分析一样准确的P-a，P-CO2测量值。
Accurate measurements of arterial P-CO2 (P-a,P-CO2) currently require blood sampling because the end-tidal P-CO2 (P-ET,P-CO2) of the expired gas often does not accurately reflect the mean alveolar P-CO2 and P-a,P-CO2. Differences between P-ET,P-CO2 and P-a,P-CO2 result from regional inhomogeneities in perfusion and gas exchange. We hypothesized that breathing via a sequential gas delivery circuit would reduce these inhomogeneities sufficiently to allow accurate prediction of P-a,P-CO2 from P-ET,P-CO2. We tested this hypothesis in five healthy middle-aged men by comparing their P-ET,P-CO2 values with P-a,P-CO2 values at various combinations of P-ET,P-CO2 (between 35 and 50 mmHg), P-O2 (between 70 and 300 mmHg), and breathing frequencies (f; between 6 and 24 breaths min(-1)). Once each individual was in a steady state, P-a,P-CO2 was collected in duplicate by consecutive blood samples to assess its repeatability. The difference between P-ET,P-CO2 and average P-a,P-CO2 was 0.5 +/- 1.7 mmHg (P = 0.53; 95% CI -2.8, 3.8 mmHg) whereas the mean difference between the two measurements of P-a,P-CO2 was -0.1 +/- 1.6 mmHg (95% CI -3.7, 2.6 mmHg). Repeated measures ANOVAs revealed no significant differences between P-ET,P-CO2 and P-a,P-CO2 over the ranges of P-O2, f and target P-ET,P-CO2. We conclude that when breathing via a sequential gas delivery circuit, P-ET,P-CO2 provides as accurate a measurement of P-a,P-CO2 as the actual analysis of arterial blood.